The disclosure relates to a semiconductor device, and more particularly, to a vertical-type semiconductor memory device.
In order to achieve excellent performance and a reduced economical cost, an increase in a degree of integration of semiconductor devices is required. In particular, a degree of integration of semiconductor memory devices is a significant factor in determining prices of products. A degree of integration of two-dimensional semiconductor memory devices according to the related art is primarily determined by the area of unit memory cells, and thus is greatly affected by the level of technology for forming fine patterns. However, high-priced equipment is used to form fine patterns, and the area of a chip die is limited. Thus, the degree of integration of the two-dimensional semiconductor memory devices is increasing but is still limited. Thus, vertical-type semiconductor memory devices having a three-dimensional (3D) structure are increasingly in demand.